Add a "fork" of musl as //fusl.

fusl/src/malloc/DESIGN

Index: fusl/src/malloc/DESIGN
diff --git a/fusl/src/malloc/DESIGN b/fusl/src/malloc/DESIGN
new file mode 100644
index 0000000000000000000000000000000000000000..58b0523ffdba15b8a0c493578458bc364f45857a
--- /dev/null
+++ b/fusl/src/malloc/DESIGN
@@ -0,0 +1,22 @@
+
+
+In principle, this memory allocator is roughly equivalent to Doug
+Lea's dlmalloc with fine-grained locking.
+
+
+
+malloc:
+
+Uses a freelist binned by chunk size, with a bitmap to optimize
+searching for the smallest non-empty bin which can satisfy an
+allocation. If no free chunks are available, it creates a new chunk of
+the requested size and attempts to merge it with any existing free
+chunk immediately below the newly created chunk.
+
+Whether the chunk was obtained from a bin or newly created, it's
+likely to be larger than the requested allocation. malloc always
+finishes its work by passing the new chunk to realloc, which will
+split it into two chunks and free the tail portion.
+
+
+